Mobile metallic domain walls in an all-in-all-out magnetic insulator
Mobile metallic domain walls in an all-in-all-out magnetic insulator
复制标题
全进全出磁绝缘体中的移动金属畴壁
DOI：
10.1126/science.aac8289
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发表时间：
2015-10-30
期刊：
影响因子：
56.9
通讯作者：
Shen, Zhi-Xun
中科院分区：
文献类型：
--
作者：
Ma, Eric Yue;Cui, Yong-Tao;Shen, Zhi-Xun
当金属经历相变并成为绝缘体时，它有时也会变得磁性有序。有可能一些金属性残留在磁区的边界，即所谓的磁区壁上，但这个问题很难在实验中直接解决。Ma等人。正是通过使用微波阻抗显微镜绘制出Nd2Ir2O7材料在低温磁绝缘阶段的电导图，才做到了这一点。磁畴壁在图像中清晰地显示为高电导区域。科学，本期第538页的微波阻抗显微镜被用来观察Nd2Ir2O7绝缘相中的导电磁畴壁。磁畴壁是具有相同磁序的不同配置的区域之间的边界。在磁性绝缘体中，磁序与其块体绝缘性能有关，人们假设磁化壁上的电学性质有很大不同，其中磁序不可避免地受到干扰。在这里，我们通过输运和空间分辨微波阻抗显微镜，在磁性绝缘体Nd2Ir2O7中发现了高导电性的磁畴壁，该绝缘体具有不寻常的全进全出磁序。磁畴壁的方块电阻几乎与温度无关，约为每平方千欧姆，表面光滑，没有择优取向，没有无序钉扎，具有强烈的热和磁场响应，符合All-In-All-Out磁序的预期。
Visualizing conducting domain walls When a metal undergoes a phase transition and becomes insulating, it sometimes also becomes magnetically ordered. It is possible that some metallicity survives along the boundaries of magnetic domains, the so-called domain walls, but the question is difficult to address directly in experiments. Ma et al. did just that by mapping out the conductance of the material Nd2Ir2O7 in its low-temperature magnetic insulating phase, using microwave impedance microscopy. The magnetic domain walls showed up clearly in the images as regions of high conductance. Science, this issue p. 538 Microwave impedance microscopy is used to visualize conducting magnetic domain walls in the insulating phase of Nd2Ir2O7. Magnetic domain walls are boundaries between regions with different configurations of the same magnetic order. In a magnetic insulator, where the magnetic order is tied to its bulk insulating property, it has been postulated that electrical properties are drastically different along the domain walls, where the order is inevitably disturbed. Here we report the discovery of highly conductive magnetic domain walls in a magnetic insulator, Nd2Ir2O7, that has an unusual all-in-all-out magnetic order, via transport and spatially resolved microwave impedance microscopy. The domain walls have a virtually temperature-independent sheet resistance of ~1 kilohm per square, show smooth morphology with no preferred orientation, are free from pinning by disorders, and have strong thermal and magnetic field responses that agree with expectations for all-in-all-out magnetic order.